Printing arrangement utilizing a continuously moving transfer band



May 5, 1970 D. B; SPAULDING PRINTING ARRANGEMENT UTILIZING A CONTINUQUSLY MOVING TRANSFER BAND 2 Sheets-Sheet 1 Filed Dec. 22, 1967 E BE as M INVENTOR DAV/O a. SPA 04 oavs BY 9 M'ITORNEY y 5, 1970 D. B. SPAULDING 3,509,816

PRINTING ARRANGEMENT UTILIZING A CONTINUOUSLY MOVING TRANSFER BAND 2 Sheets-Sheet 2 Filed Dec. 22, 1967 6 M R m m um m w n ma... A mm United States Patent 3,509,816 PRINTING ARRANGEMENT UTILIZING A CONTINUOUSLY MOVING TRANSFER BAND David B. Spaulding, Carlisle, Mass., assignor, byines'ne assignments, to International Telephone and Telegraph Corporation, Nutley, N.J., a corporation of Maryland Filed Dec. 22, 1967, Ser. No. 692,816 Int. Cl. B41f 17/10 US. Cl. 1011 2 Claims ABSTRACT OF THE DISCLOSURE A printing arrangement is provided which forms, across a gap, a transferable magnetic ink pattern on a continuously moving transfer band, and transfers said pattern across another air gap to a transversely movable record surface.

CROSS-REFERENCE TO RELATED APPLICATION This invention is related to D. B. Spaulding, filed Oct. 24, 1969, Ser. No. 677,594, entitled Printing Apparatus.

BACKGROUND OF THE INVENTION In general this invention relates to a printing arrangement which provides an endless transfer band onto which there is formed a transferable magnetic image, the image being formed across a gap and removed from the transfer band across another gap onto a transversely movable record surface.

The prior art suggests using a magnetic field to attract liquid magnetic ink, however, a transfer band is not marked, but the magnetic ink is transferred from a conventional printing plate directly to the file copy paper. In another known arrangement, a drum of two electrostatic images of opposite plurality are formed, electro static toner is applied to one image, and electrostatic and magnetic toner to the other image. The second magnetic ink tone image is then transferred by rolling contact and a magnetic field to a print paper. Another known use of magnetic ink is in an arrangement in which the ink is gravity fed by droplets from a nozzle and magnetized, dependent on the signal strength, and transversely applied to a tape to form the pattern.

Thus the prior art lacks any suggestion of projecting a magnetic ink pattern on a continuously moving and transferring transfer band, the projected ink pattern across another gap onto copy surface.

SUMMARY OF THE INVENTION An object of this invention is to provide an arrangement for projecting a temporary magnetic liquid ink pattern, across a gap, onto a moving transfer band, magnetically holding the pattern formed thereon, and projecting the pattern, across another gap, from the band onto a transversely movable record surface.

Another object of this invention is to provide an arrangement which includes the combination of forming a magnetic ink pattern on a transfer band, the ink comprising particles of a hard magnetic powder which is capable of being permanently magnetized at a magnetic station, which follows an image forming station, so as to polarize each droplet of ink on the band. The forming and magnetization stations to be followed by a transfer station of opposite polarity for transferring the magnetic image formed on the transfer band to the record surface.

According to the broader aspects of the invention there is provided a printing arrangement which includes a continuously moving transfer band, a stationary image forming means for forming a magnetic pattern upon the band, across a gap, and a printout station for transferring the 3,509,816 Patented May 5, 1970 ice magnetic image across another gap and onto a transversely movable record sheet.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring generally to FIGS. 1 and 2, the principal elements of the printing arrangement are shown. A continuously moving transfer band 11 is supported on two rollers 12, one or both of which may be powered to provide the motion of the endless band 11. The band passes, but does not touch, a stationary image forming station 13 consisting of a row of fluid expulsion nozzles 14, capable of depositing discrete fluid droplets 15 on the moving band 11, in response to electrical or other suitable pulse commands 16. The image forming station and band are arranged as shown in FIG. 2, so as to permit the formation of any image 19 in the form of a two-dimensional array of individual fluid droplets 15, without having the droplets run together and destroy the image. The images having been so formed are transported by the moving band 11 past the record sheet 17. When a predetermined group of droplets forming the image 19 are positioned opposite the desired location on the record sheet, an attractive field force arrangement 18 located directly behind the record sheet is excited, and the image placed on the transfer band at the image forming station is transferred from the moving band to the record surface.

The fluid employed in this arrangement is a magnetic ink, which comprises a suspended solution of iron or other magnetically attractive particles in a highly colored solvent or other suitable composition. The transfer band 11 is fabricated of a suitable material such as disclosed in US. Pat. No. 3,247,825, but wherein the transfer belt itself could be impregnated with magnetized particles which forms a permanent flexible magnet with north and south poles 20 located on the opposite flat sides of the band as indicated in FIGURE 2. The ink droplets 15 deposited on the band at the. image forming station, one such station could comprise an arrangement shown in US. Pat. No. 3,152,858, and are thereby held securely in place by the magnetic force exerted on each droplet by poles 20 to maintain the image integrity during the time interval intervening between the image formation and its removal at the transfer position.

The printing of the image 19 on the record sheet is achieved when the transfer band movement locates the array of ink droplets at the desired position in front of the record sheet. At this time the appropriate electrostatic or magnetic field station, located in close proximity to the record sheet, is excited and exerts an attractive force on the ink droplets suflicient to overcome the magnetic force holding the image to the transfer band, so as to rapidly attract the magnetic image to the record sheet surface. This operation takes place across the gap existing between the transfer band and the record sheet without interrupting the movement of the transfer band, and the excitation of the attractive field being of a rapid pulse nature.

Referring now to FIGS. 3 through 6, another embodiment of the arrangement according to the invention is illustrated. Continuously moving transfer band 31 is supported on two rollers 32, one or both of which may be powered, to provide the motion of the endless band. The band may be of the type with closely spaced, fine interstices for holding a liquid ink during travel as disclosed in US. Pat. No. 2,384,515. The band passes through a stationary image forming station 33, which station may be of the type disclosed in the previous reference Pat. No. 3,247,825 and is capable of forming discrete ink media droplets 34 on the moving band 31 in response to electrical or other suitable energy pulse commands 35. The image forming station and band are configured as shown in FIG. 4, including fluid expulsion nozzles 36, so as to permit the formation of any image in a two-dimensional array of individual ink media droplets 34 without the subsequent blending together of the droplets and destruction of the image 37. The image 37 having been so formed is transported by the moving band past a stationary image magnetization station 38.

The ink fiuid media 34 is comprised of a solution of fine particles of a material capable of being permanently magnetized when subjected to a magnetic field, i.e. a hard magnetic powder, one such type has a coercive force He of about 1.5 to 2.0 oersteds. As shown in FIG. 5, the mag netization station creates images formed of magnetic dipoles 39. After leaving the magnetization station, placement of a permanent magnet behind the image side of the band will cause the particles in the droplets to be attracted to the band thereby maintatining the image clarity until removal is effected onto the copy surface. However, in the event that the band surface and capillary attraction of the fluid to the band are suitable, only capillary force for retaining the image need be utilized, and no image retaining magnet 40 need be used.

The images having been so formed are transported by the moving band past the record and in close proximity to an image expulsion device 411.

When a particular group of droplets 42 forming the image 37 to be printed are opposite the location on the record sheet 43 Where printing is desired, the corresponding segment 44 of the image expulsion device and the appropriate electrostatic or magnetic field device 45 located behind the paper are simultaneously excited, and the image is rapidly transferred from the continuously moving band 31 across the gap 46 onto the record sheet 43. FIG. 6 illustrates the image expulsion device 41 consisting of an electromagnet capable of rapidly generating a magnetic polarity adjacent to the image and on the opposite side to that of the image face nearest the recording surface. A strong force tending to break the capillary retaining bond is thereby generated causing the image to be expelled toward the field station 47.

The field station 47 attractive force is utilized to attract the ink media, across the gap 46 separating the transfer band and the record surface, in a straight path of travel. Either an electrostatic or magnetic field may be employed, with the use of an' electrostatic field implying either attraction of a statically neutral image through the use of an induced field grading force, or precharging the droplets by corona discharge, or other suitable means and using a uniform electric field to create the attractive force.

I claim:

1. A transfer band printer comprising:

a continuously moving transfer band formed in a loop and adapted for receiving a transferable ink pattern;

a plurality of inking nozzles for depositing across a gap, a pattern of ink droplets which are retained on the band surface by capillary attraction;

said ink droplets including magnetic particles capable of permanent magnetization in a given orientation;

a magnetizing station positioned to magnetize said particles in said given orientation;

a transfer station for transferring said magnetized pattern, across another gap, onto a record sheet movable transversely of said band, said station including an image expulsion device having electromagnetic segments positioned to form a magnetic field opposite to said given orientation and to propel the magnetized ink particles across said other gap; and

a plurality of magnetic field devices positioned opposite said electromagnetic segments forming a magnetic field which cooperates with said expulsion device to transfer said pattern from said band to said record sheet.

2. The printer according to claim 1, including a pattern station and said image expulsion device to add to the band surface and capillary attraction for maintaining pattern clarity until transfer is effected.

References Cited UNITED STATES PATENTS 2,841,461 7/1958 Gleason 1011 XR 2,985,135 5/1961 Hickerson. 3,052,213 9/1962 Schaffert. 3,188,649 6/1965 Preisinger et al. 3,211,088 10/1965 Naiman. 3,279,367 10/1966 Brown. 3,296,965 1/1967 Reif et al. 3,359,566 12/1967 Donalies. 3,377,598 4/1968 Borman. 3,400,213 9/1968 Hell.

3,422,753 1/ 1969 Strassner et al.

EDGAR S. BURR, Primary Examiner US. Cl. X.R. l971 

